Does Rehabilitation After Total Knee Arthroplasty Work? - Feasibility Trial

The main questions it aims to answer are:

* Recruitment (Process/Resources): Are patients willing to engage, and stay, in the trial (estimated by inclusion-rate, participant retention, etc.) and what reasons do patients give for not wishing to enroll or later dropping out of the trial? (inquired face-to-face, during enrolment). * Harms (Scientific): Does the non-exercise intervention appear "safe" (i.e. not harmful) for the patients? (estimated by for instance: adverse events, reasons for dropouts and sense of security). * Trial procedure feasibility (Management/Scientific): How well does recruitment and trial procedures work at trial sites? (estimated through feedback from site personnel). * Participant (patient) experienced acceptability of their assigned intervention: An interview-based follow-up using the Theoretical Framework of Acceptability.

Participants will be randomized to one of two interventions, at discharge from the hospital, following knee replacement, which are being tested for feasibility:

1. "Usual-care" - referral to municipal (free-of-charge) physiotherapy (commonly 6-8 weeks of therapeutic exercise). 2. "Return to everyday life" - no referral to municipal physiotherapy.

Participants in both groups are encouraged to follow WHO guidelines of physical activity, to the degree that their post-surgical symptoms allow (within their orthopedic surgeon's recommendations/limitations). All participants are given a "symptom guide", meaning a folder containing information on what to expect, and when and what to react to, during their recovery after the knee-replacement.

For clarity it should be mentioned, that the quantitative and qualitative data-outputs will be reported separately for improved clarity (the study is not a mixed methods design).